1. Field of the Invention
The present invention relates to an integrated optical device and an optical module.
2. Description of the Related Art
Patent Literature 1 (International Publication No. WO2008/117460) describes a multilevel light intensity modulator including a plurality of Mach-Zehnder (MZ) modulators. In this Mach-Zehnder modulator, a transmission line propagating therethrough an electric signal is input to the corresponding modulator from a direction perpendicular to the extending direction of an optical waveguide. A transmission line for each of an input to the Mach-Zehnder modulator and an output from the Mach-Zehnder modulator is bent at an angle of 90 degrees. Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2010-185978) describes an integrated optical device including a plurality of Mach-Zehnder modulators. Non-Patent Literature 1 (“Four-Channel Arrayed Polarization Independent EA Modulator with an IPF Carrier Operating at 10 Gb/s” K. Tsuzuki, Y. Kawaguchi, S. Kondo, Y. Noguchi, N. Yoshimoto, H. Takeuchi, M. Hosoya, and M. Yanagibashi, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 12, NO 3, MARCH 2000) describes an optical device in which four electro-absorption (EA) modulators are integrated. This EA modulator is mounted in a carrier used for supplying an electric signal. A transmission line for an electric signal is input to each EA modulator in a direction perpendicular to the optical waveguide of each EA modulator.